Yi Fei, Huo Mingyue, Li Jianrui, Yu Jingjuan
State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, 100193, China.
State Key Laboratory of Plant Physiology and Biochemistry, Engineering Research Center of Plant Growth Regulator, Ministry of Education, College of Agronomy and Biotechnology, China Agricultural University, Beijing, 100193, China.
Plant J. 2022 May;110(4):1213-1228. doi: 10.1111/tpj.15725. Epub 2022 Apr 4.
Drought stress is a serious factor affecting crop growth and production worldwide. The circadian clock has been identified as key to improving regional adaptability of plants. However, our understanding of the contribution of the circadian clock to drought response and the impacts of drought stress on the circadian clock in plants is still limited. To explore the interactions between the circadian clock and drought stress, foxtail millet seedlings were treated with simulated drought (20% polyethylene glycol-6000) treatment starting at the day (DD) onset zeitgeber time 0 (ZT0, lights on) and at the night (DN) onset zeitgeber time 16 (ZT16, lights off). A high temporal-resolution transcriptomic investigation was performed using DD and DN samples collected at intervals of 2 or 4 h within a 24-h drought-treatment period. Overall, we identified 13 294 drought-responsive genes (DRGs). Among these DRGs, 7931 were common between DD and DN samples, 2638 were specific to DD, and 2725 were specific to DN. Additionally, we identified 1257 circadian genes, of which 67% were DRGs. Interestingly, with drought treatment starting at the day for 8, 12 or 16 h, the circadian phase shifted to 12 h. We also found that the circadian clock led to different day and night drought-responsive pathways. The identification of DRG_Clock (DRG and circadian clock) and DRG_NonClock (DRG and not circadian clock) genes provides a reference for selecting candidate drought resistance genes. Our work reveals the temporal drought-response process and crosstalk between drought stress and the circadian clock in foxtail millet.
干旱胁迫是影响全球作物生长和产量的一个重要因素。生物钟已被确定为提高植物区域适应性的关键。然而，我们对生物钟在干旱响应中的作用以及干旱胁迫对植物生物钟的影响的了解仍然有限。为了探究生物钟与干旱胁迫之间的相互作用，从谷子幼苗开始，在白天（DD）起始授时时间0（ZT0，光照开启）和夜间（DN）起始授时时间16（ZT16，光照关闭）用模拟干旱（20%聚乙二醇-6000）处理。在24小时干旱处理期间，每隔2或4小时收集DD和DN样本，进行高时间分辨率的转录组学研究。总体而言，我们鉴定出13294个干旱响应基因（DRG）。在这些DRG中，7931个在DD和DN样本中是共同的，2638个是DD特有的，2725个是DN特有的。此外，我们鉴定出1257个生物钟基因，其中67%是DRG。有趣的是，当干旱处理在白天开始8、12或16小时时，生物钟相位偏移到12小时。我们还发现生物钟导致了不同的昼夜干旱响应途径。DRG_Clock（DRG和生物钟）和DRG_NonClock（DRG和非生物钟）基因的鉴定为选择候选抗旱基因提供了参考。我们的工作揭示了谷子对干旱的时间响应过程以及干旱胁迫与生物钟之间的相互作用。
